Incidence
It is estimated that, in the United States in 2023, there will be 300,590 new cases of breast cancer, resulting in 43,700 deaths.10 From 2015–2019, there were 128.1 new breast cancer cases/100,000 population, which is the highest rate of cancer in the United States, regardless of sex.11 Diagnoses among patients aged 40 to 49 are rising at a faster rate than previously, about 2% per year between 2015 and 2019.
Racial and ethnic differences
In addition to the racial and ethnic epidemiologic differences in breast cancer, there are also disparities in breast cancer care and outcomes that need to be considered when making national guidelines/policy recommendations.
Black women have high mortality rates from breast cancer. While non-Hispanic White patients have the highest rates of breast cancer (TABLE 3), non-Hispanic Black patients have the highest rates of death due to breast cancer.10 There appear to be several reasons for the estimated 40%-higher rate of mortality among Black women, including:
- systemic racism in primary research, guidelines, and policy
- inequities in diagnostic follow-up and access to evidence-based cancer treatments
- biologic differences in breast cancer (ie, the incidence of triple-negative breast cancer (TNBC) is 2-fold higher in Black women compared with the other racial and ethnic groups in the United States).12-14
While prior studies have suggested that screening mammography might be less effective for patients with TNBC, a recent study demonstrated that patients who had mammography–screened-detected TNBC tumors were smaller and more likely to be node- negative compared with non-screened patients with TNBC.(14) Patients with screened-detected TNBCs were also more likely to undergo a lumpectomy instead of a mastectomy compared with non–screened detected TNBC (68.3% vs 46.1%; P = .002) (TABLE 4). These data strongly suggest that screening mammography is indeed effective in detecting TNBC at earlier stages, one of the best proxies for breast cancer mortality.
Non-White patients have higher incidence rates of breast cancer in their 40s. A second factor to consider in racial differences is the relatively higher incidence of breast cancer in Hispanic, Black, and Asian patients in their 40s compared with non-Hispanic White patients. In a recent analysis of data from 1973 to 2010 from the Surveillance, Epidemiology, and End Results (SEER) Program, the median age of patients with breast cancer in the United States was 58.0 years (interquartile range [IQR], 50.0–67.0 years).16 Across all US demographic populations by age at diagnosis, more than 20% of patients will have their initial diagnosis of breast cancer under the age of 50, and 1.55% (1 in 65) patients between ages 40 and 49 years will be diagnosed with breast cancer.4 However, among patients aged 50 and younger diagnosed with breast cancer, a significantly higher proportion are Black (31%), Hispanic (34.9%), or Asian (32.8%) versus White (23.1%) (P < .001 for all).16 So, for there to be similar racial and ethnic mammography capture rates with White patients, starting mammography screening ages would need to be lower for Black (age 47 years), Hispanic (and 46 years), and Asian (age 47 years) patients. Data from this study of the SEER database16 also demonstrated that more Black and Hispanic patients at age of diagnosis were diagnosed with advanced (regional or distant) breast cancer (46.6% and 42.9%, respectively) versus White or Asian patients (37.1% and 35.6%, respectively; P < .001 for all).
These findings led the authors of the study to conclude that the “Current [2016] USPSTF breast cancer screening recommendations do not reflect age-specific patterns based on race.” The USPSTF stated that this is one of the reasons why they reconsidered their stance on screening , and now recommend screening for all patients starting at age 40.
My current counseling approach
I encourage all racial and ethnic patients between the ages of 40 and 49 to undergo screening mammography because of the associated relative risk mortality reduction rates, which range from 15% to 50%. I also share that with my patients that, because of the younger average age of onset of breast cancer in Black, Hispanic, and Asian patients, they may derive additional benefit from screening starting at age 40.4
Impact of draft guidelines on breast cancer screening and mortality in younger patients
There is clear, unequivocal, and repeatable Level 1 evidence that screening mammography in the general population of patients aged 40 to 49 reduces breast cancer mortality. Breast cancer is the leading cause of cancer in the United States, the second leading cause of cancer mortality in patients, and 1 in 5 new breast cancer diagnoses occur in patients between the ages of 40 and 49. While recent efforts have been made to come to consensus on a screening starting age of 40 for patients at average risk for breast cancer, the USPSTF appeared to be an outlier with their 2016 recommendation to routinely start mammography screening at age 50 instead of 40.17
The USPSTF is a very important national voice in cancer prevention, and their 2023 (draft) revised guidelines to age 40 as the recommended starting screening age now agrees with the leading US guideline groups listed in Table 2. These guideline groups have gone through varying processes, and now have finally arrived at the same conclusion for age to start screening mammography in women of average risk. This agreement should come as a significant comfort to health care providers and patients alike. Changing the starting age to 40 years will result in thousands of lives and hundreds of thousands of life-years saved for patients aged 40 to 49. ●